US4275370A - Electrical overload circuit breaker - Google Patents
Electrical overload circuit breaker Download PDFInfo
- Publication number
- US4275370A US4275370A US06/058,740 US5874079A US4275370A US 4275370 A US4275370 A US 4275370A US 5874079 A US5874079 A US 5874079A US 4275370 A US4275370 A US 4275370A
- Authority
- US
- United States
- Prior art keywords
- spring
- armature
- circuit breaker
- contacts
- overload circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/40—Combined electrothermal and electromagnetic mechanisms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/14—Electrothermal mechanisms
- H01H71/145—Electrothermal mechanisms using shape memory materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/24—Electromagnetic mechanisms
- H01H71/2463—Electromagnetic mechanisms with plunger type armatures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H61/00—Electrothermal relays
- H01H61/01—Details
- H01H61/0107—Details making use of shape memory materials
- H01H2061/0115—Shape memory alloy [SMA] actuator formed by coil spring
Definitions
- This invention relates to electrical overload circuit breakers.
- Such circuit breakers are increasingly employed in place of fuses to protect circuits from overloads, and are required to open the protected circuit on the occurrence of a prolonged overload of relatively small magnitude, e.g. 50% above nominal current, and instantly on the occurrence of a high overload, e.g. 4-9 times the nominal current.
- Known overload circuit breakers employ, firstly, a bimetal strip and, secondly, a solenoid, both in series with the contacts of the circuit breaker and both arranged to cause opening of the contacts when prescribed movements of the bimetal strip and solenoid armature occur.
- a circuit breaker should occupy as little space as possible and must contain within its enclosure means for quenching the arc formed when the contacts open.
- the tripping mechanism--the bimetal strip and the solenoid-- occupy a substantial proportion of the enclosure and the volume available for arc quenching limits the overload current the circuit breaker can handle.
- the bimetal strip is dispensed with and the solenoid coil is or includes a helical spring of shape memory effect material operatively acting on the armature mechanically and adapted to urge the armature in tripping direction on being heated by current passing through the spring.
- the SME spring then acts both electromagnetically and mechanically on the armature and performs the functions of both the bimetal strip and the solenoid of previously known circuit breakers. The space within the enclosure of the circuit breaker required for the tripping mechanism is reduced, leaving more space available for arc quenching.
- a “shape memory effect material” or a “SME material” is meant a material having an elastic modulus which varies significantly with temperature in a reversible manner, over a transition temperature range.
- Such materials are well known and may comprise a suitable titanium-nickel alloy, or a Cu-Zn-X alloy where X can be aluminium, tin or silicon, or a Cu-Al-Y alloy where Y is iron, manganese or nickel.
- the preferred material is a copper-zinc-aluminum alloy.
- An SME material is capable of effecting a substantial displacement and to exert a considerable effort when subjected to temperature change within the transition temperature range.
- the SME spring in tension and to have the spring conditioned to contract axially on rise of temperature within the transition temperature range. Then, the electromagnetic attraction between the coils of the spring acts to augment the forces on the armature due to the solenoid effect and the SME effect.
- the armature is biased by a second spring which does not exhibit shape memory effect properties and which opposes the SME spring.
- the combination of the SME spring and the second or bias spring has a displacement/temperature characteristic exhibiting smaller hysteresis that when the SME spring is employed alone.
- the bias applied by the second spring may be adjustable to vary the temperature at which the tripping mechanism operates.
- the overload circuit breaker may further comprise a pair of electrical contacts which are relatively movable between closed and open positions; resilient means connected to bias the contacts to the open position; and retaining means for retaining the contacts in the closed position against the action of the resilient means, but actuable by the tripping mechanism to release the contacts.
- FIG. 1 diagrammatically illustrates the overload circuit breaker
- FIG. 2 shows on enlarged scale the shape memory effect (SME) spring and its mountings.
- SME shape memory effect
- FIG. 1 illustrates the contacts of the circuit breaker and the tripping mechanism for opening those contacts when an overload occurs.
- a pivoted main contact arm 1 carries one of a pair of electrical contacts 2 and is continually acted on by resilient means, in the form of a main compression spring 3 which urges the arm 1 in a direction to open the contacts 2.
- the contact arm 1 is also connected to retaining means, in the form of a toggle mechanism 4 which, when in the position shown, retains the contacts 2 in the closed position.
- a dolly 5 is pivotally connected to the toggle mechanism 4 in order to bring the toggle mechanism into the normal position as shown in FIG. 1.
- an overload tripping mechanism consisting of a magnetically permeable soft steel cage 6 acting as a magnetic loop.
- a central opening in the top of the cage is normally closed by an armature, which is formed by a soft steel spindle 10 and a soft steel plug 7.
- the armature is carried by the toggle mechanism 4 by means of the upper part of spindle 10 which passes through the central opening and which is fixed to the plug 7.
- the armature 7 10 is acted on oppositely by, firstly, a helical tension spring 8 of SME material, and an inner compression spring 9 of ordinary spring steel. The action of the SME coil spring 8 is thus biased by the non-SME spring 9.
- the lower part of the soft steel spindle 10 extends within the inner spring 9 and forms plug an extension of the soft steel armature 7.
- An airgap 11 is formed between the bottom of the spindle 10 and a steel calibrating screw 12 threaded into the base of the cage 6.
- the biasing spring 9 engages at its lower end against the screw 12 so that is compression can be adjusted.
- SME spring 8 The lower end of SME spring 8 is held captive in the bottom of cage 6 by having the interior of the cage threaded at 20 at the lower end to receive the lowermost coils of the spring (see particularly FIG. 2).
- the upper end of the SME spring is similarly secured to plug 7 by having the latter threaded externally at 21 to capture the uppermost coils of spring 8 (see FIG. 2).
- Compression spring 9 of non-SME material engages the lower side of plug 7 about a central boss 22 and biases SME spring 8 in tension.
- the circuit to be protected is connected in series with terminals 13 and 14, which are connected together through the contacts 2 when closed, the contact arm 1, a lead 15, the spring 8, and a further lead 16; the load current thus passes through the SME spring 8 which acts as a solenoid in conjunction with the armature 7, 10.
- the spring 8 is preferably made of a copper-zinc-aluminium alloy having a composition of 70.1% copper, 25.9% zinc and 4.0% aluminium, and heat treated to bring it to memory condition. It has a transition temperature mid-point of about 40°Cm so that as the temperature of the spring 8 rises above ambient temperature, the elastic modulus progressively increases. The spring has been stressed in tension at a temperature below the transition tension range.
- the current through the spring 8 creates a magnetic attraction between the turns of the spring tending to contract the spring axially and to urge the armature in tripping direction.
- the attraction between the turns of the spring augments the solenoid and SME forces acting on the armature.
- the contact breaker can be restored to the normal condition following an overload, by manual operation of dolly 5 to raise the toggle mechanism 4 again over-centre.
- the circuit breaker is extremely simple, both to manufacture and to assemble, consisting only of a limited number of parts, and the circuit breaker can thus be manufactured relatively cheaply.
- the fact that the main spring 3 acts directly on the contacts 2 through the arm 1 results in the opening time of the contacts being very short and allows the contact breaker to handle a high overload current.
- the volume occupied by the tripping mechanism illustrated is relatively small, thereby providing a relatively large volume in the enclosure of the circuit breaker to be utilised for a large arc quenching chamber, again to enable the circuit breaker to handle high overload currents without failure.
- the circuit through the circuit breaker i.e. between the terminals 13 and 14, is short and through relatively low resistivity materials, it can handle currents up to a high value, e.g. 5 to 80 amps nominal rating without overheating.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Breakers (AREA)
- Thermally Actuated Switches (AREA)
Abstract
Description
Claims (12)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB30681/78 | 1978-07-21 | ||
GB7830681 | 1978-07-21 | ||
GB7836850 | 1978-09-14 | ||
GB36850/78 | 1978-09-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
US4275370A true US4275370A (en) | 1981-06-23 |
Family
ID=26268291
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/058,740 Expired - Lifetime US4275370A (en) | 1978-07-21 | 1979-07-18 | Electrical overload circuit breaker |
Country Status (3)
Country | Link |
---|---|
US (1) | US4275370A (en) |
DE (1) | DE2928799A1 (en) |
FR (1) | FR2431761A1 (en) |
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4490975A (en) * | 1983-03-14 | 1985-01-01 | Raychem Corporation | Self-protecting and conditioning memory metal actuator |
US4520336A (en) * | 1983-12-01 | 1985-05-28 | Eaton Corporation | Electrothermally actuated switch |
US4551660A (en) * | 1983-07-04 | 1985-11-05 | Kabushiki Kaisha Tokai Rika Denki Seisakusho | Motor controlling switch device |
US4559512A (en) * | 1983-03-14 | 1985-12-17 | Raychem Corporation | Self-protecting and conditioning memory metal actuator |
US4675642A (en) * | 1984-01-07 | 1987-06-23 | Vdo Adolf Schindling Ag | Temperature switch |
US4829843A (en) * | 1984-08-31 | 1989-05-16 | The Furukawa Electric Co., Ltd. | Apparatus for rocking a crank |
US4901045A (en) * | 1989-03-20 | 1990-02-13 | Westinghouse Electric Corp. | Secondary circuit breaker for distribution transformers |
US4949061A (en) * | 1988-07-08 | 1990-08-14 | Messerschmitt-Boelkow-Blohm Gmbh | Electromechanical relay |
US5107235A (en) * | 1991-01-24 | 1992-04-21 | Square D Company | Current driven actuator with coupled thermal and magnetic actuating elements |
DE19508498A1 (en) * | 1995-03-09 | 1996-09-12 | Siemens Ag | Remote release mechanism for protective switch |
DE19649700A1 (en) * | 1996-11-29 | 1998-06-04 | Siemens Ag | Memory element drive device for working current or over-voltage release |
US20050069842A1 (en) * | 1997-03-18 | 2005-03-31 | Schleppenbach David A. | Apparatus and methods for a shape memory spring actuator and display |
US20060044093A1 (en) * | 2002-06-05 | 2006-03-02 | Honda Giken Kogyo Kabushiki Kaisha | Actuator |
US20080006112A1 (en) * | 2006-07-05 | 2008-01-10 | Grand Haven Stamped Products, A Division Of Jsj Corporation | Shifter with actuator incorporating shape memory alloy |
US20080018422A1 (en) * | 2004-11-22 | 2008-01-24 | Abb Patent Gmbh | Switching Device Having an Electromagnetic Release |
US20080258850A1 (en) * | 2004-11-22 | 2008-10-23 | Abb Patent Gmbh | Switching Device Having an Electromagnetic Release |
US20090025501A1 (en) * | 2006-07-05 | 2009-01-29 | Mitteer David M | Shifter with shape memory alloy and safety |
US20090128265A1 (en) * | 2007-11-15 | 2009-05-21 | General Electric Company | Secondary trip system for circuit breaker |
CN102290297A (en) * | 2011-07-28 | 2011-12-21 | 西安交通大学 | Quick release mechanism capable of preventing impact and vibration for direct current breaker |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3013016A1 (en) * | 1980-04-03 | 1981-10-08 | Brown, Boveri & Cie Ag, 6800 Mannheim | RELEASE SYSTEM OF A SELF-SWITCH TO INTERRUPT A CIRCUIT |
DE3136951A1 (en) * | 1981-09-17 | 1983-04-21 | Brown, Boveri & Cie Ag, 6800 Mannheim | "START-UP RELAY FOR ELECTRICAL SINGLE-PHASE MOTORS WITH A START-UP AUXILIARY" |
FR2557353B1 (en) * | 1983-12-26 | 1986-04-11 | Merlin Gerin | MAGNETOTHERMAL TRIGGER IN SHAPE MEMORY MATERIAL, ASSOCIATED WITH A CIRCUIT BREAKER MECHANISM |
FR2715763B1 (en) * | 1994-02-01 | 1996-03-29 | Gec Alsthom T D Inc | Mechanism for actuating a protective switch-off chamber. |
DE19542690A1 (en) * | 1995-11-16 | 1997-05-22 | Aeg Niederspannungstech Gmbh | Device for the forced disconnection of power lines in switching devices |
DE102004056282A1 (en) * | 2004-11-22 | 2006-05-24 | Abb Patent Gmbh | Switching device for an electronic assembly comprises a thermal and electromagnetic circuit breaker having a snap-on mounting interacting with an impact anchor |
DE102004056280A1 (en) * | 2004-11-22 | 2006-05-24 | Abb Patent Gmbh | Protective switch with magnetic release for e.g. motor or circuit protection, is made from alloy with magnetic shape memory |
DE102004056279A1 (en) * | 2004-11-22 | 2006-05-24 | Abb Patent Gmbh | Protective switch with magnetic and thermal release for e.g. motor or circuit protection, is made from alloy with combined thermal- and magnetic shape memory |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2443090A (en) * | 1945-08-04 | 1948-06-08 | Donald R Wise | Circuit breaker |
US2842635A (en) * | 1953-05-08 | 1958-07-08 | Fed Electric Prod Co | Circuit breaker with thermal and magnetic trip means |
US3731247A (en) * | 1971-01-08 | 1973-05-01 | American Thermostat Corp | High temperature sensing apparatus effective over extensive lengths |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE611678C (en) * | 1935-04-02 | Voigt & Haeffner Akt Ges | Overcurrent switch in which an extended knee lever keeps the release contact closed in the on position | |
DE2139852A1 (en) * | 1971-08-09 | 1973-02-15 | Battelle Institut E V | SWITCHING ELEMENT WITH TEMPERATURE-DEPENDENT SWITCHING POSITION |
DE2701884A1 (en) * | 1976-01-19 | 1977-07-21 | Delta Materials Research Ltd | CURRENT OVERLOAD PROTECTION |
CH606456A5 (en) * | 1976-08-26 | 1978-10-31 | Bbc Brown Boveri & Cie | |
CH616270A5 (en) * | 1977-05-06 | 1980-03-14 | Bbc Brown Boveri & Cie |
-
1979
- 1979-07-13 FR FR7918212A patent/FR2431761A1/en active Pending
- 1979-07-17 DE DE19792928799 patent/DE2928799A1/en not_active Withdrawn
- 1979-07-18 US US06/058,740 patent/US4275370A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2443090A (en) * | 1945-08-04 | 1948-06-08 | Donald R Wise | Circuit breaker |
US2842635A (en) * | 1953-05-08 | 1958-07-08 | Fed Electric Prod Co | Circuit breaker with thermal and magnetic trip means |
US3731247A (en) * | 1971-01-08 | 1973-05-01 | American Thermostat Corp | High temperature sensing apparatus effective over extensive lengths |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4490975A (en) * | 1983-03-14 | 1985-01-01 | Raychem Corporation | Self-protecting and conditioning memory metal actuator |
US4559512A (en) * | 1983-03-14 | 1985-12-17 | Raychem Corporation | Self-protecting and conditioning memory metal actuator |
US4551660A (en) * | 1983-07-04 | 1985-11-05 | Kabushiki Kaisha Tokai Rika Denki Seisakusho | Motor controlling switch device |
US4520336A (en) * | 1983-12-01 | 1985-05-28 | Eaton Corporation | Electrothermally actuated switch |
US4675642A (en) * | 1984-01-07 | 1987-06-23 | Vdo Adolf Schindling Ag | Temperature switch |
US4829843A (en) * | 1984-08-31 | 1989-05-16 | The Furukawa Electric Co., Ltd. | Apparatus for rocking a crank |
US4949061A (en) * | 1988-07-08 | 1990-08-14 | Messerschmitt-Boelkow-Blohm Gmbh | Electromechanical relay |
US4901045A (en) * | 1989-03-20 | 1990-02-13 | Westinghouse Electric Corp. | Secondary circuit breaker for distribution transformers |
US5107235A (en) * | 1991-01-24 | 1992-04-21 | Square D Company | Current driven actuator with coupled thermal and magnetic actuating elements |
DE19508498A1 (en) * | 1995-03-09 | 1996-09-12 | Siemens Ag | Remote release mechanism for protective switch |
DE19649700A1 (en) * | 1996-11-29 | 1998-06-04 | Siemens Ag | Memory element drive device for working current or over-voltage release |
US20050069842A1 (en) * | 1997-03-18 | 2005-03-31 | Schleppenbach David A. | Apparatus and methods for a shape memory spring actuator and display |
US7018209B2 (en) * | 1997-03-18 | 2006-03-28 | Purdue Research Foundation | Apparatus and methods for a shape memory spring actuator and display |
US20060044093A1 (en) * | 2002-06-05 | 2006-03-02 | Honda Giken Kogyo Kabushiki Kaisha | Actuator |
US20090002108A1 (en) * | 2002-06-05 | 2009-01-01 | Honda Giken Kogyo Kabushiki Kaisha | Actuator |
US7579935B2 (en) | 2002-06-05 | 2009-08-25 | Honda Giken Kogyo Kabushiki Kaisha | Actuator |
US7423505B2 (en) * | 2002-06-05 | 2008-09-09 | Honda Giken Kogya Kabushiki Kaisha | Actuator |
US20080018422A1 (en) * | 2004-11-22 | 2008-01-24 | Abb Patent Gmbh | Switching Device Having an Electromagnetic Release |
US20080258850A1 (en) * | 2004-11-22 | 2008-10-23 | Abb Patent Gmbh | Switching Device Having an Electromagnetic Release |
US20080006112A1 (en) * | 2006-07-05 | 2008-01-10 | Grand Haven Stamped Products, A Division Of Jsj Corporation | Shifter with actuator incorporating shape memory alloy |
US20090025501A1 (en) * | 2006-07-05 | 2009-01-29 | Mitteer David M | Shifter with shape memory alloy and safety |
US20080006115A1 (en) * | 2006-07-05 | 2008-01-10 | Grand Haven Stamped Products, A Division Of Jsj Corporation | Shifter with actuator incorporating magnetic unlock mechanism |
US7779715B2 (en) | 2006-07-05 | 2010-08-24 | Grand Haven Stamped Products, A Division Of Jsj Corporation | Shifter with actuator incorporating magnetic unlock mechanism |
US7814810B2 (en) | 2006-07-05 | 2010-10-19 | Grand Haven Stamped Products, A Division Of Jsj Corporation | Shifter with actuator incorporating shape memory alloy |
US8117938B2 (en) | 2006-07-05 | 2012-02-21 | Ghsp, Inc. | Shifter with shape memory alloy and safety |
US20090128265A1 (en) * | 2007-11-15 | 2009-05-21 | General Electric Company | Secondary trip system for circuit breaker |
US7911302B2 (en) * | 2007-11-15 | 2011-03-22 | General Electric Company | Secondary trip system for circuit breaker |
CN102290297A (en) * | 2011-07-28 | 2011-12-21 | 西安交通大学 | Quick release mechanism capable of preventing impact and vibration for direct current breaker |
CN102290297B (en) * | 2011-07-28 | 2013-12-11 | 西安交通大学 | Quick release mechanism capable of preventing impact and vibration for direct current breaker |
Also Published As
Publication number | Publication date |
---|---|
FR2431761A1 (en) | 1980-02-15 |
DE2928799A1 (en) | 1980-01-31 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
AS | Assignment |
Owner name: DELTA MEMORY METAL LIMITED, UNIT B10/11, FARTHING Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DELTA MATERIALS RESEARCH LIMITED;REEL/FRAME:003886/0303 Effective date: 19810423 |
|
AS | Assignment |
Owner name: AFFILIATED BUSINESS CREDIT CORPORATION, CONNECTICU Free format text: SECURITY INTEREST PURSUANT TO PATENT SECURITY AGRE;ASSIGNOR:MEMRY CORPORATION (DELAWARE CORPORATION);REEL/FRAME:007969/0916 Effective date: 19960809 |